Is it possible to make Git aware of an existing .gitmodules file?

Question

I added a submodule:

git submodule add git://github.com/chneukirchen/rack.git rack

A file .gitmodules was created like:

[submodule "rack"]
path = rack
url = git://github.com/chneukirchen/rack.git

And of course Git knows about it:

git submodule status
30fb044db6ba5ea874ebc44a43bbd80a42676405 rack (1.3.0-64-g30fb044)

I added a submodule by hand, for example, adding to that file:

[submodule "redcloth"]
path = plugins/redcloth
url = git://github.com/jgarber/redcloth.git

And I repeated the previous command:

git submodule init
Submodule 'rack' () registered for path 'rack'

git submodule update
(no output)

git submodule status
30fb044db6ba5ea874ebc44a43bbd80a42676405 rack (1.3.0-64-g30fb044)

So, as far I can see, what I added by hand is ignored. Is there some way to make Git aware of the lines added by hand in the .gitmodules file?

Note: I've also tried to add the lines by hand to the .git/config file and that didn't work either.

Answer 1

Ok, so thanks to Adam I found the answer, was kind of obvious but nevertheless, here it is:

If you check what git submodule add does, you'd notice that it does three things:

1. Adds the lines to the .gitmodules file,
2. Clones the repo in the 'path' you determined in the command, and
3. Adds the module to the .git/config file.

So, basically the only difference between a repo with a submodule added by hand and the one added via the git submodule command is the contents of the repo itself.

Answering with the same example, you should:

$ git clone git://github.com/jgarber/redcloth.git plugins/redcloth

Add the following to the .git/config file*:

[submodule "redcloth"]
url = git://github.com/jgarber/redcloth.git

Make sure at least you add them to the git repo:

$ git add plugins/redcloth

And then check if git actually is "aware":

$ git submodule status
0766810ab46f1ed12817c48746e867775609bde8 plugins/redcloth (v4.2.8)
30fb044db6ba5ea874ebc44a43bbd80a42676405 rack (1.3.0-64-g30fb044)

*note that the "path" variable you use in the .gitmodules file isn't needed in that file

Answer 2

You need to run

git submodule update --init --recursive 

UPDATE:

the submodule add command actually clones the entire repo and adds the sha1 to the index.

This may be new behaviour as compared to previous versions of git, the clone was not done immediately.

If you don't have an entry in the index pointing the module to a particular commit, git submodule update refuses to do anything. This seems to be new behaviour.

Hope this helps.